1. Field of the Technology
The present disclosure relates generally to voice communication sessions in a computer network which includes a wireless local area network (WLAN), and more particularly to the use of a global virtual local area network (VLAN) in the computer network for voice communication sessions to avoid IP address reassignment for inter-subnet handoffs for mobile communication devices.
2. Description of the Related Art
In wireless communication networks, such as wireless local area networks (WLANs) which operate in accordance with 802.11-based standards, one or more network identifiers may be utilized by mobile communication devices to identify a WLAN to connect with and obtain communication services. One of these services may be a voice telephony service, such as the voice telephony service based on Voice over IP (VoIP) communications via the WLAN. For 802.11-based WLANs, network coverage is provided by a plurality of wireless access points (APs) and the network identifiers are referred to as extended service set identifiers (ESSIDs).
During a VoIP communication session, the mobile device may move from a radio frequency (RF) coverage area of one wireless AP to the RF coverage area of another wireless AP. If this happens, the VoIP session of the mobile device is “handed-over” to the other wireless AP. During a handoff, the mobile device associates with the new wireless AP with use of an ESSID so that the VoIP traffic may be exchanged between the new wireless AP and the mobile device (“layer-2 roaming” transition). Such a transition is mostly transparent to the end user of the mobile device and provides for minimal if any disruption of the VoIP session. However, the new wireless AP may be part of an IP subnet segment of the WLAN that is different from that of the previous wireless AP. If the mobile device is handed-off to a wireless access point in a different subnet segment, a new IP address of the subnet segment must be dynamically assigned to the mobile device by the network. Thus, a “layer-3 roaming” transition must take place in this situation. Unfortunately, the layer-3 roaming transition during the VoIP session may be disruptive of the VoIP session.
Accordingly, there is a need for communication methods and apparatus which overcome the deficiencies of traditional techniques.